# Paycheck Calculator — MCP tool `findutils:paycheck_calculator`

Estimate United States take-home pay from a gross salary: federal income tax using the published bracket tables and the standard deduction, plus the employee half of FICA — 6.2% Social Security up to the annual wage base, 1.45% Medicare on everything, and the additional 0.9% Medicare tax above the threshold for your filing status. Traditional 401(k) contributions reduce income tax but not FICA; cafeteria-plan contributions such as an HSA or health premiums reduce both, which is why they are separate inputs. Covers the tax years in the published tables. State and local income tax are NOT included, so the result is an upper bound on take-home for anyone in a state that taxes wages.

- Category: finance
- MCP server: https://mcp.findutils.com/ (Streamable HTTP, no API keys, 120 req/min per IP)
- REST endpoint: POST https://api.findutils.com/api/tools/paycheck-calculator/execute (no API keys, 60 req/min per IP)
- Reference page: https://findutils.com/mcp/paycheck-calculator/
- Same tool on the other surface: https://findutils.com/api/paycheck-calculator/

## Connect

```bash
claude mcp add findutils --transport http https://mcp.findutils.com/
```

Claude Desktop (`claude_desktop_config.json`):

```json
{
  "mcpServers": {
    "findutils": {
      "url": "https://mcp.findutils.com/"
    }
  }
}
```

## Call the tool (verified example)

```bash
curl -X POST https://mcp.findutils.com/ \
  -H "Content-Type: application/json" \
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "paycheck_calculator",
      "arguments": {
        "gross_pay": 4000,
        "pay_frequency": "biweekly",
        "filing_status": "single",
        "tax_year": "2025"
      }
    }
  }'
```

## Input schema

| Argument | Type | Required | Description |
|---|---|---|---|
| `gross_pay` | number | yes | Gross pay for one pay period, before any deduction. |
| `pay_frequency` | string (weekly \| biweekly \| semimonthly \| monthly \| annual) | no | How often you are paid. biweekly is every two weeks (26 a year); semimonthly is twice a month (24). Default biweekly. Default: `"biweekly"`. |
| `filing_status` | string (single \| married_joint \| married_separate \| head_of_household) | no | Federal filing status. Default single. Default: `"single"`. |
| `tax_year` | string (2024 \| 2025) | no | Tax year to use. Default 2025. Default: `"2025"`. |
| `retirement_401k` | number | no | Traditional 401(k) or 403(b) contribution per pay period. Reduces federal income tax; does not reduce Social Security or Medicare. Default 0. Default: `0`. |
| `cafeteria_plan` | number | no | Section 125 cafeteria-plan contribution per pay period — HSA, FSA or health insurance premiums. Reduces federal income tax AND FICA. Default 0. Default: `0`. |
| `extra_withholding` | number | no | Additional federal withholding per pay period, from step 4(c) of Form W-4. Default 0. Default: `0`. |

Example arguments (verified):

```json
{
  "gross_pay": 4000,
  "pay_frequency": "biweekly",
  "filing_status": "single",
  "tax_year": "2025"
}
```

## Also a REST endpoint

```bash
curl -X POST https://api.findutils.com/api/tools/paycheck-calculator/execute \
  -H "Content-Type: application/json" \
  -d '{
    "gross_pay": 4000,
    "pay_frequency": "biweekly",
    "filing_status": "single",
    "tax_year": "2025"
  }'

# Parameter schema
curl https://api.findutils.com/api/tools/paycheck-calculator
```

Full REST reference: https://findutils.com/api/paycheck-calculator/ · OpenAPI 3.1 spec: https://findutils.com/api/openapi.json

---
Full catalog: POST https://mcp.findutils.com/ with method `tools/list` · https://findutils.com/mcp/ · https://findutils.com/llms.txt